The present invention relates to a device for measuring object distance or an in-focus position to be focus controlled used for a camera in which object distances or focus adjusting condition of a plurality of objects in the photographing scene are measured by projecting a plurality of bundles of ray on objects and receiving the reflected lights thereof.
As conventional so-called multipoint object distance measuring devices in which object distances of a plurality of objects in the photographing scene are measured, known are a device in which the focus of a focusing lens is adjusted simply on the nearest object according to object distance data of respective distance measuring areas (disclosed, for example, in Japanese Laid-open Patent Publication No. 62-14015), and another device in which object distance of central portion of the photographing scene and one or both of objects distance of adjacent portion thereto are measured, and the focus of a focusing lens is adjusted on an object of the mean object distance among the measured object distances (disclosed, for example, in Japanese Laid-open Patent Publication No. 59-146028).
However, in these devices, the focus of a focusing lens is adjusted simply on the nearest object or on an object of the mean distance of a plurality of object distances. Accordingly, in the former case, if an object locates at a nearer position than a position of a main object intended by a photographer to be focus adjusted, focus is sometimes adjusted on that unintended nearer object. And in the latter case, sometimes the main object comes outside the depth of field when another object such as a background has a strong influence. In the conventional devices, focus of a focusing lens cannot always be adjusted on a photographer's intended main object as abovementioned, which calls for improvements of conventional devices.
Further, in the conventional devices, no account is taken of the flashlight photographing. In other words, in the flashlight photographing, sometimes focus is adjusted on an object farther than the flashlight reaching distance, and in such a case, time is wasted for judging which is the main object and an erroneous photographing occurs due to under exposure.